You can save this as a Map Border File and then create a Custom Map File. (Click the SAVE MAP BORDERS button…then click the CREATE CUSTOM MAP button.)
Tip:
You can control the width of any corridor map. Click VIEWMAP DISPLAY OPTIONS, and the Map Display Options dialog box appears.
Map Display Options menu.
Click on the MAP BORDERS tab. Near the bottom of the box, drag the Corridor Width slider bar back and forth along the scale to increase or decrease the width of your corridor. This allows you to make very narrow corridors, which in turn results in conveniently small Custom Map file sizes.
Corridor Width 
slider bar
Map Borders tab in the Map Display Options dialog box. Drag the Corridor Width slider bar to the left to narrow corridor width. Drag the slider bar to the right to widen corridor width.
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